Mine roof supports



1968 w. J. ADCOCK ETAL 3,370,431

MINE ROOF SUPPORTS Filed July 25, 1966 5 Sheet$-Sheet l w. J. ADCOCK ETAL 3,370,431

I Feb. 27, 1968 MINE ROOF SUPPORTS Filed JuIy 25, 1966 3 Sheets-Sheet 2 7 'nlOI 1968 w. J. ADCOCK ETAL 3,370,431

MINE ROOF SUPPORTS Filed July 25, 1966 3 Sheets-Sheet I5 United States Patent 3,370,431 MINE RGOF SUPPORTS William J. Adcoclr, London, and William V. Sheppard, Hurley, England, assignors to Coal Industry (Patents) Limited, London, England, a British company Filed July 25, 1966, Ser. No. 567,424 Claims priority, application Great Britain, Aug. 3, 1965, 33,133/65 11 Claims. (Cl. 6145) This invention relates to mine roof supports particularly mine roof supports used in a longwall system of mining for supporting the roof of a longwall face.

Various proposals have been made for providing roof supporting structures which comprise extensible hydraulic prop members interposed between a floor beam and a rooof beam, extension of the prop members causing the roof beam to bear against the roof thereby effecting support of the roof. Such roof supports have been proposed for use ina longwall system employing an armoured flexible scraper conveyor adapted to be advanced transversely of its length, the roof supports and conveyor being operable as a composite unit so that the supports may be advanced incrementally behind the conveyor.

Hitherto such support systems have been of two main kinds. One kind, the so-called frame support, has props and roof and floor beams arranged in a single line in each support unit. The units may be arranged to advance by means of a ram connecting the unit either to the face conveyor structure or to an adjacent support unit. These supports have a tendency to be unstable, especially when used on inclined seams or when adapted for use in seams over 5 ft. thickness. The other kind of support system is the called chock support. These supports have a substantial base area with at least three prop supports carried on a base of square, rectangular, T-shaped or tri angular plan. Roof beams mounted on the props support the roof. The later supports do not sufier from the disadvantage of instability but do not have the disadvantage that, when the props are retracted and the roof beams are lowered from a roof supporting position for advance of the support unit, a relatively large area of roof is exposed. It is advantageous that as small an area of roof as possible is exposed during retraction of a support to reduce the likelihood of falls of roof occurring over the support.

It is also desirable that, after a longwall mining machine adapted to cut a strip of mineral from the face, has passed the support units the newly exposed roof is supported immediately after the passage of the machine. This is particularly important when mining systems are employed which do not allow the conveyor to be advanced immediately after cutting run of the machine. In the frame support system it is sometimes a feature of the system that some of the units can be advanced immediately after the passage of the machine, as described for example, in British patent specification No. 823,121.

An object of the invention is to provide a roof support which combines the advantages of the frame support with the advantages of the chock support. A further object is to provide a roof support having inherent stability which can be advanced immediately behind the mining machine and which supports substantially all the exposed roof adequately at all times.

Accordingly the invention provides in one aspect a roof support unit for a longwall system of mining comprising two different support elements, each element having a roof beam supported by two or more props and extending beyond said props in cantilever manner, and further comprising advancing means for moving the two elements of the support unit relative to one another in the direction of advance of the support unit, the roof beam of one 3,3 70,431 Patented Feb. 27, 1968 element of the support unit having a first part which extends in the direction of advance of the support unit parallel to and spaced laterally from the roof beam of the other element, and a second part extending transversely from the first part and to the rear of the other element with respect to the direction of advance of the support unit.

Preferably the first and second parts together form a roof beam which is L-shaped in plan view, the shorter limb of the L constituting said transverse part of the roof beam.

The advancing means may comprise a hydraulic doubleacting ram interconnecting the two elements, the ram being arranged to advance each element in turn with one of the elements being disposed in a roof supporting posi tion constituting an abutment against which the ram may act.

According to a further aspect the invention provides longwall mining assembly comprising a conveyor adapted to extend along a mine face, a mining-machine, and a series of roof support units adapted to be positioned when in use on that side of the conveyor remote from the mine face, each of said units having two different support elements adapted to be arranged alternately along the mine face, and advancing means for moving the two elements of each support unit relative to one another in the direction of advance of the face, each element having a roof beam supported on two or more props, the roof beam of one element of each support unit having a first part which extends in the direction of advance of the support unit and parallel to and spaced laterally from the roof beam of the other element and a second part extending transversely from the first part and to the rear of the other element with respect to the direction of advance of the support units, and the roof beam of each said other element having a cantilever extension which in use projects forwardly over the conveyor in the direction of travel of the support units in such a manner that said other element can be advanced towards the conveyor after passage of the mining machine past the support unit and before advance of the portion of conveyor in front of the element.

Further features of the invention appear from the following description given by way of example and with reference to the accompanying drawing in which:

FIGURES 1 and 2 are plan views and FIGURE 3 is an end view of the support,

FIGURES 4 and 5 are schematic plan views of a mining arrangement incorporating the roof supports of the invention and,

FIGURES 6, 7 and 8 are sections on the lines VIVI, VII-VII and VIII-VIII respectively in FIGS. 4 and 5.

Referring to the drawings the roof support unit has two elements, a first element 1, hereinafter referred to as the chock element, and a second element 2 hereinafter referred to as the frame element.

The frame element 2 has a straight roof beam 3 mounted on a pair of hydraulic extensible props 4 and vertically above a straight floor beam 12, the roof and floor beams extending parallel to the direction of advance of the support unit. The roof beam 3 is longer than the floor beam 12 and has a cantilever extension 3a projecting forwardly of the support unit from the forward prop 4. The extension 341 may be strengthened by a strut (not shown) attached to and extending upwardly from either the floor beam 12 or the forward prop 4 to the underside of the extension 3a.

The chock element 1 is L-shaped in plan view and has an L-shaped roof beam 6 and an L-shaped floor beam 13 interconnected by three hydraulic extensible prop 4. The longer limbs of the L-shaped floor and roof beams are arranged parallel to and spaced from the beams of the frame unit 1' and the roof beam 6 has a cantilever I extension 6a projecting forwardly of the support unit, and the shorter limb projects transversely of the longer limb and behind the frame element 1 with respect to the direction of advance of the support unit. The longer limb of the roof beam 6 is carried on two props 4 and the shorter limb on one prop 4.

The elements 1 and 2 are interconnected by a doubleacting hydraulic ram 7, which is adapted to advance the elements relative to one another as the face is advanced. The ram 7 consists of a piston and cylinder arrangement, the piston 8 being attached to the frame element 2 and the cylinder 9 being attached to the chock element 1 and slidable relative to the frame element 2. The ram 7 and props 4 are supplied with pressure fluid for their opera-' tion by a hydraulic pump (not shown) in known manner, which may conveniently be situated remotelfrom the sup port unit, pressure fluid being supplied along fluid feed hoses (not shown) extending along the face. Suitable fluid control valves (not shown) are fitted in known manner to the support unit for effecting control of the support operations. Such valves may be arranged to operate automatically'in known manner in response to the support monitoring system or they may be arranged to be operated manually.

To maintain the frame element 2 in its correct position in relation to the chock element a guide 16 is attached to the shorter limb of the floor beam 13' of the chock element 1 and enclose the floor beam 12' of the frame element. The frame element 2 can move longitudinally of the guide 16 but is preventedfrom lateral movement by the sides of the guide 16.

The roof beams 3 and 6 of the two elements 1 and 2 may be slidably connected to each other at their adjacent longitudinal sides to help maintain stability of the support unit. The connection may be by means of a rod on one element engaging in a slot in a bracket carried on the other element i The roof beams may comprise a pair of parallel spaced apartbox-section girders secured to a roof-engaging plate, the top of the props being located in a seating between the girders. The roof beams and floor beams may each be in two or more sections pivotally attached to one another to allow flexing of the support unit when there are undulations in the floor or roof.

Towards the rear of the chock element shields 10 are fitted to prevent roof material which has fallen down behind the support unit fromflushing on to the support unit and interfering with its advance. A tunnel (not shown) may be formed in the transverse floor beam of the chock element to allow debris which hascollected on the floor to pass under the beam as the support is advanced.

Referring now particularly to FIGS. 4-8 a row of the support units is positioned on the goaf side of the face conveyor 11, ie at the opposite'side of the conveyor to the mineral seam 14, and the cantilever extensions 6a and 3a of the beams 6 and 3 project forwardly of the support unit to support the roof over the conveyor 11 and the newly. exposed roof on the face side of the conveyor 11. The roof of the mineral face is thus supported by a plurality'of support units arranged side-by side along.

the length. of the face and closely adjacent one another so that substantially all the roof extending from .the mineral to be mined to the rear of the support units is supported, the two difierent elements alternating along the face. R'ams (not shown) are also provided to connect some or all of the support units to the face conveyor- 11 in order that the conveyor 11 may be advanced after the mineral has been cut and loaded on to theconveyor. Conveniently, every fifth roof support unit has "such a ram.

7 The roof beams may eachcarry a. telescopic extension inknown manner for forward support of the roof aheadof. the roof beam cantilever extension.

A mining machine 15, in this instance a ranging drum shearer of known kind, is adapted for, reciprocal movement along the face 14 and is mounted on the face conveyor 11 which is of the well-known armoured scraper chain type. The mining machine 15 operates by firstly extracting the upper part of'the mineral in the seam during one traverse of the face, and during the return run along the face the lower part of the seam is extracted, the extracted mineral being deposited on the conveyor 11 during each traverse and carried along and away-from the face.

In FIG. 4 the machine 1-5 is shown traversing the face from right to left as shown and extracting the upper part.

of the mineral seam. After the machine 15 has passed the rowof support units the roof beam 3 of the frame element 2 is lowered and the element 2 is advanced by operation of the ram 7. The roof beam 3 is raised against the roof after the advance by extension of the props 4, and the cantilever extension 3a supports the newly exposed roof behind the machine 15.

In FIG. 5 the machine 15 is shown traversing the face from left to right as shown and is extracting the lower part of the mineral seam. After the machine has extracted the full seam section the face conveyor 11 is advanced, by operation of the advancing rams, in a snaking manner, and after advance of the conveyor the roof beams 6 of the chock elements 1 are lowered from the roof and the chock elements 1 are advanced successively behind the machine 15. After advance of the chock elements 1 the cycle' of operations is complete and the sequence is repeated.

The roof support units of the invention may also be em-' during a single traverse of the face. With this arrangement the frame elements may be advanced immediately behind the machine and the conveyor and chock elements are advanced immediately after the frame elements.

It will be appreciated that the support unit of the inven tion effects support of the roof of the excavation up to the goaf edge of the supported area at all times except when the chock elements are being advanced so that even during and after the advance of the frame elements a regular, row of roof support beams extend along the goaf edge of said area thus ensuring an even line of roof collapse behind-the support units. In addition the support unit enables the roof exposed bythe passage of the mining machine to be immediately'supported.

We claim:

1. A roof support unit for a longwall system of mining comprising two different support elements, each element having a floor beam on which is mounted two or more props and a roof beam supported on said props and extending beyond said props in cantilever manner and further comprising advancing means for moving the two elements of the support unit relative to one another in the direction of advance of the support unit, the roof beam of one element of the support unit having a first part which extends in thedirection of advance of the support unit parallel to and spaced laterally from the roof beam of the .2. A roof support unit according to claim 1' wherein the first and=second parts together form a roof beam is L- shaped in'plan view, the shorter limb of the L constituting said transverse part of the roofbeam.-

3. A roof support unit according to claim 1 wherein the advancing means comprises a hydraulic double-acting ram interconnecting the two elements, the ram being arranged to advance each element in turn with one of the elements being disposed in a roof-supporting position constituting an abutment against which the ram may act.

4. A roof support unit according to claim 1 wherein the transverse part of the roof beam of said one element is supported on one prop and the other part of the roof beam is supported by at least one other prop.

5. A roof support unit according to claim 1 wherein the roof beam of said other element is mounted on two props spaced longitudinally of the beam.

6. A roof support unit according to claim 1 wherein the two elements of the support unit are interconnected by means adapted to permit relative movement in the direction of advance.

7. A roof support unit according to claim 1 wherein each element, the floor beam of said one element is L- shaped in plan view and the fioor beam of said other element is parallel and adjacent the longer limb of the L of said one element.

8. A roof support unit according to claim 7 wherein the floor beams of each element are interconnected by guide means.

9. A longwall mining assembly comprising a conveyor adapted to extend along a mine face, a mining machine, and a series of roof support units adapted to be positioned when in use on that side of the conveyor remote from the mine face, each of said units having two different support elements adapted to be arranged alternately along the mine face and advancing means for moving the two elements of each support unit relative to one another in the direction of advance of the face, each element having a floor beam on which is mounted two or more props and a roof beam supported on said props, the roof beam of one element of each support unit having a first part which extends in the direction of advance of the support unit and parallel to and spaced laterally from the roof beam of the other element and a second part exten ding transversely from the first part and to the rear of the other element with respect to the direction of advance of the support units and the roof beam of each said other element having a cantilever extension which in use projects forwardly over the conveyor in the direction of travel of the support units in such a manner that said other element can be advanced towards the conveyor after passage of the mining machine past the support unit and before advance of the portion of conveyor in front of the element.

10. A longwall mining assembly according to claim 9 wherein some or all of the roof support units each comprise a ram connected between the conveyor and the support unit for advancing the conveyor using the roof support unit as an abutment.

11. A longwall mining assembly according to claim 9 wherein the mining machine is adapted to extract firstly the upper part of a mineral seam during one traverse along the longwall face and secondly the lower part of the mineral seam during the return traverse along the face and said other element is adapted to be advanced relative to the conveyor and said one element after said traverse of the machine.

References Cited JACOB SHAPIRO, Prima'ry Examiner. 

1. A ROOF SUPPORT UNIT FOR A LONGWALL SYSTEM OF MINING COMPRISING TWO DIFFERENT SUPPORT ELEMENTS, EACH ELEMENT HAVING A FLOOR BEAM ON WHICH IS MOUNTED TWO OR MORE PROPS AND A ROOF BEAM SUPPORTED ON SAID PROPS AND EXTENDING BEYOND SAID PROPS IN CANTILEVER MANNER AND FURTHER COMPRSING ADVANCING MEANS FOR MOVING THE TWO ELEMENTS OF THE SUPPORT UNIT RELATIVE TO ONE ANOTHER IN THE DIRECTION OF ADVANCE OF THE SUPPORT UNIT, THE ROOF BEAM OF ONE ELEMENT OF THE SUPPORT UNIT HAVING A FIRST PART WHICH EXTENDS IN THE DIRECTION OF ADVANCE OF THE SUPPORT UNIT PARALLEL TO AND SPACED LATERALLY FROM THE ROOF BEAM OF THE OTHER ELEMENT AND A SECOND PART EXTENDING TRANSVERSELY FROM THE FIRST PART AND TO THE REAR OF THE OTHER ELEMENT WITH RESPECT TO THE DIRECTION OF ADVANCE TO THE SUPPORT UNIT. 